• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.883-887
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• 2011

Location-based service (LBS) is becoming an important part of the information technology (IT) business. Localization is a core technology for LBS because LBS is based on the position of each device or user. In case of outdoor, GPS - which is used to determine the position of a moving user - is the dominant technology. As satellite signal cannot reach indoor, GPS cannot be used in indoor environment. Therefore, research and study about indoor localization technology, which has the same accuracy as an outdoor GPS, is needed for "seamless LBS". For indoor localization, we consider the IEEE802.11 WLAN environment. Generally, received signal strength indicator (RSSI) is used to obtain a specific position of the user under the WLAN environment. RSSI has a characteristic that is decreased over distance. To use RSSI at indoor localization, a mathematical model of RSSI, which reflects its characteristic, is used. However, this RSSI of the mathematical model is different from a real RSSI, which, in reality, has a sensitive parameter that is much affected by the propagation environment. This difference causes the occurrence of localization error. Thus, it is necessary to set a proper RSSI model in order to obtain an accurate localization result. We propose a method in which the parameters of the propagation environment are determined using only RSSI measurements obtained during localization.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.5
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• pp.799-812
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• 2017

Backfill grouting and realistic convergence distribution were not properly considered in previous studies on 2D numerical analysis of a shield TBM tunnel. In this study, a modeling method was suggested to cope with this problem by considering a realistic convergence distribution and proper properties of backfill grouting. To this end, the influence of gap parameter and depth of rock cover on volume loss and composed of ground volume loss around tunnel excavation and surface volume loss were analyzed with a single layer of weathered soil. As a result, most of surface settlements were occurred immediately after excavation. Additional, as depth of rock cover and gap parameter increased, the influence range of surface settlement curves obtained from 2D numerical analyses became broader than a suggested theoretical equation. Therefore, it is inferred that gap parameter should be applied based on load distribution ratio and the property of backfill grouting properly considered for the estimation of the precise behavior of a shield TBM tunnel in 2D numerical analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.359-364
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• 2004

In this paper, we implemented real-time speaker undependent speech recognizer that is robust in noise environment using DSP(Digital Signal Processor). Implemented system is composed of TMS320C32 that is floating-point DSP of Texas Instrument Inc. and CODEC for real-time speech input. Speech feature parameter of the speech recognizer used robust feature parameter in noise environment that is transformed feature space of MFCC(met frequency cepstral coefficient) using ICA(Independent Component Analysis) on behalf of MFCC. In recognition result in noise environment, we hew that recognition performance of ICA feature parameter is superior than that of MFCC.

• Communications of Mathematical Education
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• v.24 no.4
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• pp.949-974
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• 2010

The purpose of the study was to investigate how students' understanding was formed for solving the algebra problems involving parameters in a computer algebra environment. The teaching experiment has been conducted with 6 high school students. As a result, students studied the parameter in different roles such as placeholder, changing quantity, unknown and generalizer. The results indicate that a computer algebra environment offers opportunities for algebra activities that may support the development of understanding of the concept of parameter.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.433-435
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• 2007

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.364-370
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• 2011

Water quality criteria for human health protection are derived based on the human health risk assessment. Water quality criteria in Korean freshwater bodies have been derived according to the equations developed by the US Environmental Protection Agency. The equations include the fish intake parameter, which is very important factor that significantly influences on the criteria derivation. So far, several fish intake values were used in human health risk assessment for water quality standards and effluent standards. However, these values are not consistent and they refer to various sources. Therefore, there is a need to suggest the most appropriate value of fish intake parameter to derive freshwater quality criteria in Korea. In this study, national and international fish intake values were widely collected and evaluated to select the adequate value of fish intake parameter that can be applied in Korea. The USEPA presented fish intake parameter as the 17.5 g/day for general adults and sport fishers and 142.4 g/day for subsistence fishers. In Korean reports, wide range values of 2 to 67.7 g/day were suggested as fish intake value. These values included finfish and shellfish intakes in common but had various habits. This study found that the 52.4 g/day suggested in Korean Exposure Factors Handbook published by the Ministry of Environment in 2007 seemed to be the suitable fish intake parameter to derive the freshwater quality criteria in Korea. The value is based on water corrected intakes of finfish and shellfish present in freshwater and coastal areas. We expect that this report can be useful to select suitable fish intake value in human health risk assessment for establishing freshwater quality standard in Korea.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.308-308
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• 1998

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.7
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• pp.175-182
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• 2018

The purpose of this study is to analyze the effect of sleep environment on individual sleep and to calculate optimal sleep environment. The input and output data sets are selected and the optimized sleep environment information is calculated using the neuro-fuzzy technique. Provides optimal sleep environment considering sleep duration. The arousal ratio calculated by the proposed method is 12%, which is at least 5% lower than the previous studies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.469-472
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• 2005

This paper propose about effective speech feature parameter that have robust character in effect of noise in realizing speech recognition system. Established MFCC that is the basic parameter used to ASR(Automatic Speech Recognition) and DCTCs that use DCT in basic parameter. Also, proposed delta-Cepstrum and delta-delta-Cepstrum parameter that reconstruct Cepstrum to have information for variation of speech. And compared recognition performance in using HMM. For dimension reduction of each parameter LDA algorithm apply and compared recognition. Results are presented reduced dimension delta-delta-Cepstrum parameter in using LDA recognition performance that improve more than existent parameter in noise environment of various condition.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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• pp.511-515
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• 2005

CBOD(carbonaceous BOD) decay rate was investigated for the execution of water quality model in Nakdong-Rive basin. Estimation of laboratory-derived CBOD decay rate, $k_l$ and CBOD decay rate in natural waters, $k_d$ were carried out. Hydraulic factors were applied for the calculation of $k_d$. Values of biochemical oxygen demand were investigated in Weagwan, Koreong, Jeokpo, Namgi and Mulgeom sites for the four times. The ranges of $k_l$ value were $0.04{\pm}0.01{\sim}0.14{\pm}0.03$. The values of $k_l$ in upstream sites were much larger than those in the downstream sites. The values of $k_d$ were 0.025, 0.036, 0.005 and 0.001 at Weagwan, Jeokpo, Namgi and Mulgeom, respectively, indicating that values of $k_d$ were generally larger than those of $k_l$.